Once converted, the object code can be run at any time. This process is called compilation. All of the object files used in a program must be combined before the program can be run. This is done using a linker tool, which takes one or more objects and groups them into a single executable or a library. Compilers have several advantages:.
Compilers have several disadvantages:. Compilers are also classified as single-pass, multi-pass, load-and-go, debugging and optimization. Classification is done on the basis of what function does a compiler perform and how it has been constructed. Despite these complexities, the basic task of compiler remains same. The compilation is performed in two parts, analysis part and synthesis part. The analysis part breaks the source code into constituent pieces and forms the intermediate representation of the source code.
The synthesis part forms the target code from the intermediate representation. Lexical analyzer, syntax analyzer, semantic analyzer, intermediate code generator, code optimizer, code generator, Symbol table and error Handler. The assembler takes as input the assembly code generated by the compiler and translates it into relocatable machine code. Let us see how machine code is different from assembly code.
Assembly code is the mnemonic version of machine code. It means it assembly code uses names for representing operations and it even gives names to the memory addresses.
On the other hands, the machine code uses binary codes for representation of operations and memory addresses. As it checks line by line, the scanning time is lower. But the overall execution time is higher. Interpreter displays an error at a time. The programmer should fix that error to interpret the next line. In addition to high level languages and machine language, there is another language called the assembly language. Assembly language is in between the high level languages and machine language.
It is closer to machine language than high level languages. It is also called low level language. This language is not easily readable and understandable by the programmer like a high level programming language. The assembler works as the translator in converting the assembly language program to machine code. Am I missing something? If I am correct, the backend performs optimization in an intermediate language, generation of machine code, and optimization of the machine code, and each of the three tasks can be done in more than one ways.
Is the intermediate language an assembly language? I guess yes, but your reply mentions that an assembler does its job in only one way. Show 2 more comments. Wandering Logic Wandering Logic I would expect the difference between an Assembler A and a Compiler C to be among other things: One line of source code relates directly to one CPU opcode A or not C Highly dependent on the actual CPU A or machine independant C We tend to call assembly language "low level" and the source language a compiler understands "high level" this is gross simplification, but still.
I typically see them as four stages: The first stage reads the actual source code and creates an internal representation. This stage knows the actual source language. The second stage looks at the internal representation and does a number of optimizations. Nowadays, the compiler would typically look for making the program faster and not caring for if it gets larger.
The optimizing is done on the internal representation. Interestingly, parts of this could be generic for several different languages. The third stage takes the internal representation and creates actual code for the selected CPU. There might be several different versions of this stage, targeting different CPU-s. In effect you could write source code once and then compile it for different CPUS-s.
Final preparations for "packaging" the program this stage could be a linker. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password.
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